compounding HOTLINE

APRIL 01, 2007

Martin A. Erickson III, RPh

Q.
I am a pharmacist in Mexico. A patient is allergic to
most oils and wants injectable estradiol. I tried saline,
polyethylene glycol 400, benzyl alcohol, and polysorbate 80,
but the suspended particles were too large for injection.

A.
Estradiol is "...practically insoluble in water; soluble 1 in 28
of alcohol [ethanol], 1 in 435 of chloroform, and 1 in 150
of ether; soluble in acetone, dioxan, and solutions of
fixed alkali hydroxides; sparingly soluble in vegetable oils"
(Martindale. The Extra Pharmacopoeia. 29th ed. London,
England: Pharmaceutical Press; 1989:1407). Estradiol salts follow
a similar pattern; they are practically insoluble in water.
Here are a few suggestions: If parenteral administration is
required, try patch testing the patient for allergy to oils, seeking
one yielding no reaction. If you can, switch the patient to
either transdermal administration (pluronic lecithin organogel
gel vehicle) or oral capsules or troches for buccal or sublingual
absorption of the estradiol.

Estradiol 5 mg/mL in oil injection,calculated to make 100 mL

Ingredients:

Estradiol 0.5 g

Benzyl alcohol 5 mL

Sesame oil qs ad 100 mL

Supplies:

Sterile 0.2-μm filter (oil-compatible) or dry heat sterilizer

Procedure:

1. Accurately weigh/measure each ingredient.

2. Add the estradiol to the benzyl alcohol and mix well.

3. Add sufficient sesame oil to the mixture in (1) to bring
to total final volume and mix well.

4. Sterilize the solution either by filtration or in dry heat.*

5. Package in sterile, tight, light-resistant containers.

Notes:

This preparation should be compounded only in accordance
with USP <795> and <797>. This preparation is for
intramuscular injection.

No claims are made as to the uses, safety, efficacy, or
bioavailability of this product. The formula is for informational
purposes only.